Tiny ants invade UK with ‘super’ sprawling colonies

Three new infestations of an invasive garden ant—known for building massive colonies of tens of thousands of insects—have been found in the UK this year. Researchers warn their impact on biodiversity could be huge.

First discovered in 2009, there are now a total of six known UK infestations of the Lasius neglectus, which thrive in greenhouses and domestic gardens. Originating in Asia, they are likely to have arrived in the UK through the import of plants from infected areas.

Despite its name, the super ant is smaller than the common native UK variety, but builds “super” colonies with many queens and interconnected nests that can stretch for miles.

This trait allows the alien species to out-compete native ants commonly found in UK gardens. Living in extended colonies in large numbers, the super ant is able to out-compete for aphids and space.

“Apart from being slightly smaller, the invasive garden ant looks a lot like our common native garden ant so they can be difficult to recognize. These new ants are not aggressive, they do not sting, and they pose no harm to humans beyond people finding it unpleasant to have an infestation,” says Elva Robinson of the University of York.

(Credit: Phillip Buckham-Bonnett)

It is estimated that invasive species cost the UK £1.7billion every year through damage and management costs.

“We think the invasive ants have the potential to have a big impact on the native ecosystem. In the sites we have studied, it is clear they are excluding the native ants. They are clearly dominating, and where they cluster, native species are being pushed out,” says Robinson, a lecturer in ecology in the biology department. “…we don’t yet know whether these ants will be able to thrive outside areas of human habitation.”

She believes many more sites are yet to be uncovered.

(Credit: Phillip Buckham-Bonnett)

Since 2014, Robinson has worked alongside PhD student Phillip Buckham-Bonnett to establish the extent of the invasion in the UK. Their work has formed the basis of a Rapid Risk Assessment submitted to the government’s Animal & Plant Health Agency in June.

Showing an increase in the rate of new “super ant” discoveries, it offers recommendations for management on a national scale and will inform decision-making on UK biosecurity.

“Gaining a strong understanding of its new place in the native habitat will help manage the situation,” says Robinson, “and we are on the look-out for new sites in likely areas and can verify new sites as reported by pest control, as garden ants can be difficult for members of the public to identify.”